Ancash Earthquake of 1970

The earthquake, which lasted for about 45 seconds, occurred at 15:23:31 local time.

The epicenter of this quake was located 35 km off Peru coast in the Pacific Ocean. The quake having a magnitude of 7.9 to 8.0 on the Richter scale, showed an intensity of 8 on the Mercalli intensity scale, used to measure the intensity of the earthquakes. Tremors were also felt in the neighboring countries, Brazil and Ecuador to be precise.

The northern wall of the Nevado Huascarán, a mountain in the Yungay province, was destabilized due to the earthquake. This destabilization triggered an avalanche that buried the towns of Yungay and Ranrahirca under rock debris, ice and snow. A 3000 ft wide and 1 mile long mass of glacial ice and rock detached itself from the mountain. It skidded for approximately 11 miles and came down on Yungay town. This mass of ice was moving at a speed of more than 100 miles an hour. On its way, it collected glacial deposits, rocks and mud, and by the time it came down on the village at the foot of the mountain, it comprised of 80 million cubic meters of matter, that buried the entire town beneath it.

The 1970 Ancash earthquake or Great Peruvian Earthquake was an undersea earthquake that occurred on May 31 of that year. Combined with a resultant landslide, it was the worst catastrophic natural disaster ever recorded in the history of Peru.
The earthquake affected the Peruvian regions of Ancash and La Libertad. The epicenter of the earthquake was located 35 km off the coast of Casma and Chimbote on the Pacific Ocean, where the Nazca Plate is being subducted by the South American Plate. It had a magnitude of 7.9 to 8.0 on the Richter scale and an intensity of up to 8 on the Mercalli scale. No significant tsunami was reported.

The death toll of this earthquake was over 66,000. It is the 4th most deadly earthquake of the world in the 20th century. This disastrous earthquake destroyed about 200,000 homes and buildings and left approximately 800,000 people homeless in a region of 40,000 square miles.